Heating elements are generally known and are used, for example, as seat or wall heaters.
Such heating elements are known from German application DE 10 2005 044 490 A1. The heating element comprises at least one layer comprising a matrix made up of functional fibers, whereby the matrix is electrically conductive and/or heatable, and whereby the matrix can be connected to a source of current or voltage via contact lines. The heating element can be used in the automotive sector, whereby such heating elements are employed especially for heating the seats of vehicles.
Electrically compressible and conductive pastes for the production of heating elements are likewise known, for example, from European patent application EP 1 284 278 A2. The aqueous coating composition contains a conductive powder in which a core is coated with a conductive layer. In this case, a core made of glass is preferably coated with silver. The pastes described there are used to coat flat layers, especially textiles and non-wovens, thereby imparting them with an electrically conductive finish. Such coated layers can be further processed into flexible printed conductors. However, it is a drawback here that, because of the binder, the prior-art pastes are no longer stretchable and no longer thermally deformable after they have been applied onto the layer and have hardened. A layer coated with the paste is thus likewise no longer stretchable. Consequently, the paste cannot be used where there is a need for the material to be stretchable.